Semiconducting nanowires (NWs) are important "building blocks" for potential electrical and electromechanical devices. Here, we report on the mechanical properties of supercritical fluid-grown Ge NWs with radii between 20 and 80 nm. An analysis of the bending and tensile stresses during deformation and failure reveals that while the NWs have a Young's modulus comparable to the bulk value, they have an ultimate strength of 15 GPa, which is the maximum theoretical strength of these materials. This exceptional strength is the highest reported for any conventional semiconductor material and demonstrates that these NWs are without defect or flaws that compromise the mechanical properties.

The development of semiconductor nanowires has recently been the focus of extensive research as these structures may play an important role in the next generation of nanoscale devices. Using semiconductor nanowires as building blocks, a number of high performance electronic devices have been fabricated. In this review, we discuss synthetic methodologies and electrical characteristics of Si, Ge, and Ge/Si core/shell nanowires. In particular the fabrication and electrical properties of a variety of nanowire-based field effect transistors (FETs) are discussed. Although the bottom-up approach has the potential to go far beyond the limits of top-down technology, new techniques need to be developed to realize precise control of structural parameters, such as size uniformity, growth direction, and dopant distribution within nanowires to produce nanowire-based electronics on a large scale.